This invention generally relates to the art of electrical connectors and, particularly, to a connector for mounting on a printed circuit board, the connector having solder tails with improved latching configurations.
FIG. 8 shows a conventional electrical connector, generally designated 10, designed for mounting on a top or front side 12a of a printed circuit board 12. A connector includes a dielectric housing, generally designated 14, which mounts a plurality of conductive terminals, generally designated 16. The terminals have solder tail portions 18 which extend through selected holes 20 in the circuit board. The solder tails are soldered, as at 22, to appropriate circuit traces on a bottom or rear side 12b of the circuit board. The connector may include hold-down members 24 at opposite ends thereof (only one end being shown in the drawing) for securing the connector to the circuit board.
Problems are encountered in soldering terminal tail portions 18 to the circuit board. Specifically, during soldering, the circuit board is heated at such an elevated temperature that it may become bent as shown in FIG. 8, leaving a space or gap 26 between the connector housing and the board. As a result, some of the solder tails may be pulled away from the circuit board and their associated circuit traces, effectively peeling the printed circuit off of the circuit board.
Attempts have been made to solve these problems as shown in Japan Patent Applications Laid-Open No. 4-163864 and No. 8-293339. In those disclosures, the soldering tails are slit and bent to define latch sections on opposite sides thereof, or the terminal is stamped out of spring metal material and a resilient latch tongue is formed on one side thereof. In either system, a strong force is required to insert the soldering tails into and through the holes in the circuit board. These insertion forces increase with the ever-increasing density of the connector requiring increasing numbers of terminals, and, therefore, it is difficult if not impossible to insert plural tails simultaneously through holes in the circuit board. The present invention is directed to solving these problems by an improved solder tail configuration.
An object, therefore, of the invention is to provide a new and improved electrical connector for mounting on a printed circuit board having a plurality of through holes.
Another object of the invention is to provide a new and improved tail configuration for the solder tails of such a connector.
In the exemplary embodiment of the invention, the connector includes a dielectric housing having a plurality of conductive terminals mounted thereon. Each terminal includes a tail portion for passing through a selected one of the through holes in the printed circuit board. Each tail portion has a first side and a latch hook projecting from a second side opposite the first side. The width of the tail portion between the first side and a tip of the latch hook is less than a diameter of the selected through hole. Therefore, each solder tail can be inserted from one side of the printed circuit board through the selected through hole with minimum insertion forces, and with the latch hook being engageable with an opposite side of the printed circuit board.
According to one aspect of the invention, the latch hook has an angled leading surface for guiding the respective tail portion into the selected through hole. An abrupt latch surface is provided behind the angled leading surface for engaging the opposite side of the printed circuit board.
According to another aspect of the invention, a given pair of the terminals have tail portions with latch hooks directed toward each other. These facing latch hooks can be provided in a single row of terminals.
According to a further aspect of the invention, the tail portions of the terminals have biasing projections at the first sides of the terminals. The biasing projections are spaced from the latch hooks for engaging the insides of the through holes and biasing the latch hooks into engagement with the opposite side of the printed circuit board when the latch hooks clear the through holes.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.